ISL78235R5668 Datasheet, PDF (1/20 Pages) Intersil Corporation – Automotive 5A Synchronous Buck Regulator

DATASHEET
Automotive 5A Synchronous Buck Regulator
ISL78235R5668
The ISL78235R5668 is a highly efficient, monolithic,
synchronous step-down DC/DC converter that can deliver 5A
continuous and up to 8A pulsed output current from a 2.7V to
5.5V input supply. The device uses peak current mode control
architecture to achieve very low duty cycle operation at high
frequency with fast transient response and excellent loop stability.
The ISL78235R5668 integrates a low ON-resistance P-channel
(35mΩ, typical) high-side FET and N-channel (11mΩ, typical)
low-side FET to maximize efficiency and minimize external
component count. The 100% duty cycle operation allows less
than 250mV dropout voltage at 5A output current. The
operating frequency of the Pulse Width Modulator (PWM) is
adjustable from 500kHz to 4MHz. The default switching
frequency of 2MHz is set by connecting the FS pin high.
The ISL78235R5668 can be configured for discontinuous
(PFM) or forced continuous (PWM) operation at light load.
Forced continuous operation reduces noise and RF
interference, while discontinuous mode provides higher
efficiency by reducing switching losses at light loads.
Fault protection is provided by internal hiccup mode current
limiting during short-circuit and overcurrent conditions. The
device also integrates output overvoltage and
over-temperature protections. A power-good monitor indicates
when the output is in regulation. The ISL78235R5668 offers a
1ms Power-Good (PG) timer at power-up.
When in shutdown, the ISL78235R5668 discharges the output
capacitor through an internal 100Ω soft-stop switch. Other
features include internal fixed or adjustable soft-start and
internal/external compensation.
The ISL78235R5668 is available in a 3mmx3mm 16 Ld Thin
Quad Flat No-lead (TQFN) Pb-free package with an exposed pad
for improved thermal performance. The ISL78235R5668 is
rated to operate across the temperature range of -40°C to
+85°C.
Features
• 2.7 to 5.5V input voltage range
• 5A continuous; 8A pulse output current operation
• 2MHz default switching frequency
• 100ns guaranteed phase minimum on-time for wide output
regulation
• Adjustable switching frequency from 500kHz to 4MHz
• External synchronization from 1MHz to 4MHz
• Optional PFM mode for light-load efficiency improvement
• Very low ON-resistance HS/LS switches: 35mΩ/11mΩ
• Internal 1ms or adjustable external soft-start
• Soft-stop output discharge during disable
• OTP, OCP, output OVP, input UVLO protections
• 1% reference accuracy over-temperature
• Up to 95% efficiency
• AEC-Q100 qualified
Applications
• Automotive infotainment power
• DC/DC point-of-load modules
• μC/µP, FPGA and DSP power
• Video processor/SOC power
• Li-ion battery powered devices
Related Literature
• ISL78235 Datasheet
L
2.7V TO 5.5V
C_OUT
C_IN
16 15 14 13
VIN ₁
VDD ₂
PG ₃
SYNC ₄
ISL78235R5668
12 ^PGND
11 ^PGND
10 ^SGND
9 ^FB
56 78
V_{OUT 5A LOAD}
DSP, FPGA
FIGURE 1. TYPICAL APPLICATION: 5A BUCK REGULATOR
100
90
80
70
V_OUT = 1.2V; T = -40°C
60
V_OUT = 1.2V; T = +25°C
V_OUT = 1.2V; T = +105°C
50
40
0
1
2
3
4
5
6
7
8
OUTPUT LOAD (A)
FIGURE 2. EFFICIENCY vs LOAD (V_IN = 5V)
January 21, 2016
1
FN8769.1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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